The invention concerns a measuring probe for the determination of ion concentrations in liquids, for pH measurements and the like.
U.S. Pat. No. 3,787,307 describes a measuring probe wherein the steel tube carrying the measuring probe is glass-lined on the inside and the outside and surrounds an enameled, rod-like steel body carrying the reference electrode. The lower end of the steel rod is widened in such a manner that a junction may be inserted between the adjoining enameled surfaces, through which junction the reference liquid may be brought into contact with the liquid to be measured. Compared with the familiar single rod measuring systems (combination electrodes) with glass electrodes, such measuring probes have the advantage of being sufficiently mechanically stable, thereby making possible measurement of the pH-value in chemical vessels with running agitators where considerable mechanical stresses occur. The use of mechanically sensitive single rod measuring systems in pipe lines with high flow velocities or in high viscosity liquids or liquids containing solids, necessitates application of special protective devices, such as protective baskets, sheet metal baffles or wire lattices. These devices may result in delayed indication, falsified measuring values or in extreme cases even a non-functioning of the single rod measuring systems. A disadvantage of the familiar enameled probes is that they cannot be manufactured with a diameter as small as 12 mm so as to replace mechanically sensitive combination electrodes having such a small diameter.
It is therefore the purpose of the invention to improve an enameled measuring probe as described above, largely avoiding the described drawbacks and difficulties, providing--a mechanically stable construction--as small model as possible, so as to be comparable with the dimensions of customary combination electrodes system, can be produced, making possible a broader application of such measuring electrodes, and also including reduced manufacturing costs.